JP3369675B2 - Measuring method of position and orientation of lead terminals in electronic components - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, as shown in FIG. 1, molds a package of a main part such as a semiconductor chip with a synthetic resin, and projects each lead terminal 3 protruding from both ends of the mold part 2. In the surface mount type electronic component 1 which is bent substantially parallel to the bottom surface 2a of the mold portion 2, the posture of the bent portion of each lead terminal 3 and the height of the lead terminal 3 relative to the reference bottom surface 2a. It relates to a method of measuring position.

[0002]

2. Description of the Related Art Generally,
In order to mount the surface-mounting type electronic component 1 of this type on a printed circuit board (not shown), adhesive is applied to the bottom surface 2a of the mold section 2, and after temporary mounting on the printed circuit board, The lead terminals 3 are soldered to the electrode pads on the printed board.

Therefore, as shown in FIG. 2B, when the lead terminal 3 is located higher than the bottom surface 2a of the molded portion 2 of the electronic component 1 or the bent shape of the lead terminal 3 is inappropriate, The lead terminal 3 hits the surface of the printed circuit board 4, and a gap is created between the bottom surface 2a and the surface of the printed circuit board, resulting in insufficient adhesive strength for temporary adhesion, and the electronic component falls off before the soldering work. Further, when the lead terminal 3 is located lower than the bottom surface 2a, the gap between the lead terminal 3 and the surface of the electrode pad 5 on the printed circuit board 4 becomes too large when temporarily bonded, and the surface mounting electrode pad 5 is soldered. There are problems such as instability.

Therefore, it is necessary to strictly control the height position and bent shape of each lead terminal 3 with respect to the bottom surface 2a.

Therefore, conventionally, when the bending process of the lead terminal 3 is completed, the bottom surface 2 of the mold portion 2 which becomes the reference position is formed.
The height e of each lead terminal 3 with respect to a is measured for each electronic component 1 by the method described below, and only those within the allowable range are shipped as acceptable products.

In the first conventional measuring method, as shown in FIGS. 9 and 10, a projector 100 configured to emit a laser beam from a slit-shaped window 100a, and the laser beam is received by a light receiving slit 101a. A pair of left and right lead terminals 3 in the electronic component 1 are arranged between the light projector 100 and the light receiver 101 so as to receive a laser beam by using an optical length measuring sensor including the light receiver 101.
Assuming that the height H1 from the top surface 2b to the bottom surface 2a of the mold part 2 is constant (identical), the top surface 2
An operation of measuring the light receiving length S at the light receiving slit 101a corresponding to the height dimension from b to the tip of the lead terminal 3 and subtracting the height dimension H from this dimension S (e = S
-H), the protrusion height e of the lead terminal 3 is increased.
Is to ask.

According to this measuring method, as shown in FIG. 10, when the protruding heights of the left and right lead terminals 3a and 3b are different, only the protruding height of the higher lead terminal 3 can be measured. Moreover, if the arrangement postures of the electronic component 1 and the light receiver 101 with respect to the horizontal plane are tilted, the light receiving length S and the height dimension H are also changed, which causes a problem that a measurement error becomes large. Further, it is assumed the the height H is constant, dimensional errors of the mold for molding the mold section 2,
The height dimension e of the lead terminal 3 cannot be accurately measured because of variations in the mold clamping degree, synthetic resin material, etc., and the lead terminal 3 as shown in FIG.
It was not possible to detect a defect in the bending posture in which the tip end of the is inclined with respect to the bottom surface 2a.

As a second conventional measuring method for solving this problem, as shown in FIG. 11, an eddy current type proximity sensor 10 is used.
2, 103 are arranged close to each other so as to face each lead terminal 3 made of metal, and the distance between the surface of each lead terminal 3 and the tip of the proximity sensor 102, 103 is to be measured. When a metal such as iron is placed in a high frequency magnetic field, an eddy current is generated on the surface of the metal by electromagnetic induction according to the magnetic field strength and the distance. The eddy current generates a magnetic field in a direction opposite to the magnetic field (Lenz's law). Therefore, when the metal approaches the high frequency magnetic field, the effect of reducing the strength of the magnetic field is utilized, and the proximity sensor is used. Is composed of a high-frequency generating coil, and the distance between the sensor and the metal is known by measuring the degree to which the original magnetic field is canceled and weakened when it is brought close to the metal.

With this structure, as in the prior art, it is assumed that the height dimension H1 from the top surface 2b to the bottom surface 2a of the mold portion 2 is constant, and a pair of the reference surface (the top surface 2b of the mold portion 2) is used. Proximity sensor 10
The installation heights H2 up to the lower ends of 2, 103 are set to be constant, and the proximity sensors 10 are installed from the upper surface of each lead terminal 3.
The distance S1 to the lower end of 2, 103 is measured, and the installation height H
The projection height e (= H2-H1-S1) is obtained by executing a calculation for subtracting the height H1 and the distance S1 from 2 by the control device 104 such as a microcomputer.

Also in this measuring method, as in the second measuring method, the arrangement posture of the electronic component 1 is inclined with respect to the horizontal plane, the error in the arrangement height of the proximity sensors 102 and 103, the inclination θ of the installation posture, etc. The measurement distance S1 and the installation height H2 also fluctuate, which causes a problem that a measurement error increases, and it is assumed that the height dimension H1 is constant. Since the dimensional error of the mold, the degree of mold clamping, the synthetic resin material, and the like cause variations, the height e of the protrusion of the lead terminal 3 e
Can not be measured accurately.

Further, although it is more advanced than the first measuring method in that the proximity sensors 102 and 103 can measure the individual lead terminals 3 and 3, when the area of the metal portion of each lead terminal 3 and 3 is small. Has a small eddy current,
There is a problem that the measurement result becomes unstable and accurate position measurement (distance measurement) cannot be performed.

The present invention has been made to solve these problems, and an object of the present invention is to provide a method for accurately and quickly measuring the position / orientation of a lead terminal in an electronic component. is there.

[0013]

In order to achieve the above object, the invention according to claim 1 measures the position and / or the posture of a pair of lead terminals bent and protruding from both ends of a mold portion in an electronic component. In the method, one light source
Parallel light from the mold and the pair of left and right lead ends
Irradiate from the side with the child at once and place it on the mold part.
The reference part and the measured parts of the left and right lead terminals.
The image data of the projected image of the range to be captured is captured by the image pickup means, and the image data of the range including the measured site and the reference site of each lead terminal is subjected to image processing for each one lead terminal section, and then the It is characterized in that the geometrical position / orientation of each measured part with respect to the reference part is measured.

Position of the lead terminal of the invention according to claim 2
Method of measuring the orientation is a method for measuring the position and / or orientation of the pair of lead terminals projecting bent from both ends of the mold parts in the electronic component, parallel from one light source
Side surface between the mold and the pair of left and right lead terminals
Irradiate at once from the reference part in the mold part
And the part to be measured of the pair of left and right lead terminals.
Image data of the shadow image through means for separating the projected image.
The image data corresponding to each of the lead terminals is captured in a side view of the electronic component, the image data of each of the lead terminals is subjected to image processing, and then the geometrical portion of each measured portion with respect to the reference portion is geometrically processed. It is characterized by measuring the position and orientation.

[0015]

[Embodiments] Next, embodiments embodying the present invention will be described. FIG. 3 shows a surface mount type electronic component 1 such as a chip resistor.
The process of bending the lead terminal 3 in the (molded portion 2 having a length of about 5 mm, a width and a height of about 3 mm in the embodiment) is schematically illustrated, and the elongated lead frame 1 is shown.
A pair of frame frames 11, 1 extending in the longitudinal direction at 0
The tie bars 13 are continuously provided between the two, and the lead terminals 3a, 3b are projected in a flat plate shape at both ends of the mold portion 2 arranged at a constant interval between the lead terminals 3a, 3b. In the first bending step, after bending 90 degrees toward the bottom surface 2a in the middle of the longitudinal direction and bending it into an L-shape, by bending the near side of the mold section 2 further 90 degrees, each lead terminal 3a, The tip side of 3b is formed so as to be substantially parallel to the bottom surface 2a of the mold part 2.

FIG. 4 is a schematic view of a measuring apparatus system according to the measuring method of the present invention, in which the bending-completed electronic components 1 are provided in one frame 12 of the lead frame 1 arranged at regular intervals. The hole 14 is engaged with a guide pin (not shown) provided on the outer periphery of the transfer reel 15 which is intermittently rotated by the step motor 17 and is intermittently fed in the direction of arrow A. Reference numeral 18 is a pressing roller for pressing the other frame 11 against the outer peripheral surface of the transfer reel 15 (for preventing floating).

On the outer peripheral surface of the transfer reel 15, the bottom surface 2a of the mold part 2 and the left and right lead terminals 3a, 3b of the electronic component 1 are transferred so that the top ends thereof face up. The pair of image pickup means 20 and 21 such as a two-dimensional CCD image sensor and a television camera are provided on the left and right lead terminals 3.
This is for separately imaging the points such as the tip portions of a and 3b.

In the embodiment, the light from the light source 22 is reflected by the mirror 23.
Parallel light is projected to project the tip parts of the left and right lead terminals 3a and 3b and the bottom surface 2a of the mold part 2 in a side view of the electronic component 1 through the half prism 24. Then, the image that has been transmitted horizontally is input to one of the image pickup means 20 arranged in the horizontal direction, and an image is picked up so that the lead terminal 3a on one side and the bottom surface 2a serving as a reference surface fit in one screen. The other image pickup means 2 arranged in the vertical direction
Vertical light reflected by the metal thin film or the dielectric multilayer film 24a on the inclined surface of the half prism 24 is input to 1 and an image is picked up so that the other lead terminal 3b and the bottom surface 2a, which is also the reference surface, enter one screen. To do. Like this, 2
The two image pickup means 20 and 21 are arranged in the axial direction at right angles to each other because the distance between the two lead terminals 3a and 3b, which is the measured portion, is small, and thus the image pickup means having a larger shape cannot be arranged in parallel.

Reference numerals 25 and 26 denote the image pickup means 20 and 2 respectively.
1 is an image memory for storing the image data obtained in 1. The image processing device 27 having an arithmetic processing unit (CPU) such as a personal computer processes these image data for grayscale enhancement processing and smoothing of the image. Binary processing including the above, and calculation processing such as coordinate detection and inclination detection of a plurality of measurement sites on the lead terminal 3 and the bottom surface 2a serving as a reference surface are executed.
Reference numeral 28 is an auxiliary memory such as a hard disk. The central controller 29 controls the operation of the image processing device 27 and the step motor 17, and the detector 30 for detecting whether or not the electronic component 1 as the object to be measured is at a predetermined measurement position. In addition, C allows the measurer to visually confirm the measurement site or the like.
An operation panel 32 such as an RT 31 and a keyboard for command operation is also connected.

Next, the measuring method by this measuring device system will be explained. In FIG. 7A, the left lead terminal 3a which is the measured portion and the bottom surface 2 which is the reference surface in the vicinity thereof are shown.
FIG. 7B shows an image after the image data in the range including a is binarized (the bright part is replaced with white and the dark part is replaced with black). FIG. 7B also shows the right lead terminal 3b and its vicinity. The image after binarizing the image data in the range including the bottom surface 2a which is the reference surface is shown.

On each screen of FIGS. 7A and 7B, reference lines 33 and 34 are displayed on the screen, and a plurality of reference lines 33 from the reference line 33 on the left screen to the bottom surface 2a which is the reference surface are displayed. Establish a perpendicular line to the measurement points XL1 and XL2 of
By measuring 1 and L2, two measurement points XL1,
Knowing the distance XLo between XL2, tan (θLx) = (L
The inclination angle θLx of the bottom surface 2a with respect to the reference line 33 on the screen can be calculated by the calculation of the formula 1-L2) / XLo. FIG. 7A shows the inclination angle θL of the bottom surface 2a.
The case where x is zero is shown. Further, the length (distance) L3 of the perpendicular of the at least one measurement point XL3 to the reference line 33 in the lead terminal 3a is measured, and the projection height eL of the left lead terminal 3a with respect to the bottom surface 2a is calculated from the calculation of eL = L3-L1. Can be asked.

Similarly, on the screen of FIG. 7B, the right lead terminal 3b is also perpendicular to the plurality of measurement points XR1 and XR2 on the bottom surface 2a from the reference line 34, and the distances R1 and R2 are set. By measuring, two measurement points XR
If the distance XRo between 1 and XR2 is known, tan (θRx) =
The inclination angle θRx of the bottom surface 2a with respect to the reference line 34 on the screen can be calculated by calculating the expression (R1−R2) / XRo. Then, the length (distance) R3 of the perpendicular line to the reference line 34 of at least one measurement point XR3 in the lead terminal 3b is measured, and the projection height eR of the left lead terminal 3b with respect to the bottom surface 2a is calculated from the calculation of eR = R3-R1. Can be asked.

FIG. 8 shows the case where the bottom surface 2a has an inclination angle θRx with respect to the reference line 34. In this case, the bottom surface 2a is located from two points F and G on the reference line 34 which are separated by a horizontal distance XRo.
A perpendicular line is erected with respect to the distance R1 between the point XR1 and the point F on the bottom surface 2a and the distance R2 between the point XR2 and the point GJ. From the values of these two distances R1 and R2, the tilt angle θRx is calculated by executing the calculation as described above. Next, a second reference line 34a parallel to the bottom surface 2a is displayed on the screen from the tilt angle θRx, and the scanning line 34 parallel to the second reference line 34a.
b is moved to perform scanning so as to find the uppermost point K on the lead terminal 3b, and a scanning distance (distance between two points J and K) R
Calculate 3. From this distance R3, the vertical distance between the scanning line 34b and the bottom surface 2a (distance between the two points I and XR3) eR = (R1-R3) cos (90 ° -θRx) Can be asked.

When the image pickup means 20 and 21 respectively obtain image data of a range including the measured portions of the lead terminals 3a and 3b and the reference plane 2a, the image pickup means 20 and 21 are used.
If the magnification of the optical system is too high, it is difficult to distinguish the bending state of each lead terminal, the distance between multiple measurement points becomes too short, and the measurement error may increase.
It should be measured at an appropriate magnification. Further, in order to reduce the measurement error, an average value of the measurement results of several times may be obtained.

In the above image processing, the bottom surface 2a
The image pattern including the and lead terminals is registered (stored) in advance.
Alternatively, the image recognition work such as the search work for the measurement site may be speeded up.

The acceptable range of the protruding heights eR and eL of the electronic component 1 in this embodiment is 0 to +100 μm, and the allowable range of the inclination angles θRx and θLx is ± 5 degrees.

In the above embodiment, each lead terminal 3a, 3b
We measured the position and posture of the measured part after the completion of the bending process to the U shape, but when measuring the accuracy of the L-shaped bending in the previous stage, or when making each lead terminal into a Z shape when viewed from the side. in bending the electronic component, when measuring the gap between the contact surface of the bottom surface of the mold portion as a reference plane to the electrode pads of the lead terminals may also be capable of applying the method of the present invention is not needless to say .

[0028]

As described above, claim 1
According to the invention described in 1 and 2, collimated light from one light source
From the side surface of the mold and the pair of left and right lead terminals.
Irradiate at a time from the
Projection of the range including the measurement site of the pair of left and right lead terminals
Since the image data of the image is captured by the image pickup means,
Of the reference part and the pair of left and right lead terminals
Image data as a fixed part without being interfered with each other
Obtainable.

Therefore, it becomes possible to independently measure the position and the posture of each lead terminal with respect to the reference portion, and the range including the measured portion of each lead terminal and the reference portion is defined as one. Since it is captured as image data and image processed, it is possible to correct the influence of the inclination posture of the reference part, etc., to eliminate the factor that causes the measurement error, and to perform the measurement easily, quickly, and accurately. Play.

According to the method of claim 2,
If a plurality of lead terminals are obtained as one image data together with the reference part, the measurement error will be large, but if a plurality of image pickup means are arranged side by side in the same direction, the size of the electronic device will be reduced so that each measured part cannot be imaged. for parts, the mode
Of the reference part and the pair of left and right lead terminals
The image data of the projected image in the range including
Each of the tracks is separated by means of separating the projected image such as rhythm.
The side of the electronic component by the imaging means corresponding to the terminal position
Visually capture the above image data for each lead terminal
Since the image processing is performed, it is possible to perform the measurement with the measurement error reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of an electronic component.

FIG. 2A is a side view showing the position and posture of the lead terminal when the electronic component is a non-defective product, and FIG. 2B is a side view when the electronic component is a defective product.

FIG. 3 is a perspective view showing a mounting state of electronic components on a lead frame and a sequence of bending lead terminals.

FIG. 4 is a schematic diagram of a measuring device system.

FIG. 5 is a schematic perspective view of an image pickup section by an image pickup unit.

FIG. 6 is a schematic plan view of an image pickup section by an image pickup means.

FIG. 7 is an explanatory diagram of a screen.

FIG. 8 is an explanatory diagram showing a state where the bottom surface 2a of the mold portion 2 is inclined.

FIG. 9 is a perspective view showing a first measuring method of a conventional technique.

FIG. 10 is a side view showing a first measuring method.

FIG. 11 is a side view showing a second measuring method of the conventional technique.

[Explanation of symbols]

1 electronic components 2 Mold part 2a bottom 3,3a, 3b Lead terminal 10 lead frame 15 Transfer reel 17 step motor 20, 21 Imaging means 22 Light source 24 Half prism 25,26 image memory 27 Image processing device 29 Central control unit

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Claims (2)

(57) [Claims] 1. A method for measuring the position and / or posture of a pair of lead terminals, which are bent and protrude from both ends of a mold part in an electronic component , comprising:
Irradiate at once from the side with the lead terminals of the
Measurement of the reference part and the pair of left and right lead terminals
Image data of the projected image of the range including the part
Captured, the image data of the area including the site and a reference site to be measured of the lead terminals, and image processing for each said one lead terminal section, then, the geometrical position of each measurement site relative to the reference sites A method for measuring the position / orientation of a lead terminal in an electronic component, characterized by measuring the attitude. 2. From both ends of a mold portion of an electronic component
Position and / or shape of a pair of lead terminals that bend and project
In the method for measuring the force, parallel light from one light source is paired with the mold part on the left and right sides.
Irradiate at once from the side with the lead terminals of the
Measurement of the reference part and the pair of left and right lead terminals
The image data of the projection image of the range including the part and
Is captured by a side view of the electronic component by an image pickup means corresponding to each of the lead terminal portions via a means for separating the image data, image data of each of the lead terminal portions is subjected to image processing, and then each of the target portions with respect to the reference portion is processed. A method for measuring the position / orientation of a lead terminal in an electronic component, which comprises measuring the geometrical position / orientation of a measurement site.